Solved Examples on Human Health and Disease

Infections with Salmonella Pullorum usually cause very high mortality in young chickens and turkeys within the first 2–3 weeks of age.

Question2: Which of the following is the infective stage of the malarial parasite (Plasmodium)? [CPMT 1974, 80; AFMC 1985; MP PMT 1993, 2001; Manipal MEE 1995]

(a) Gametocyte

(b) Merozoite

(c) Sporozoite

(d) Trophozoite

Answer: c

Solution:

Sporozoite is the infectious form of the malaria parasite, which is injected into people by mosquitoes.

Question3: Which one of the following conditions though harmful in itself is also a potential saviour from a mosquito borne infectious disease? [CBSE PMT 2003]

(a) Leukemia

(b) Thalassaemia

(c) Sickle cell anaemia

(d) Pernicious anaemia

Answer: c

Solution:

Those who are carriers for the sickle cell disease (with one sickle gene and one normal hemoglobin gene, also known as sickle cell trait) have some protective advantage against malaria. Hence, the frequencies of sickle cell carriers are high in malaria-endemic areas.